1. Technical Field
The present invention generally relates to a powder container for containing powder such as toner and an image forming apparatus such as a copier, a printer, a facsimile machine, a plotter, or a multifunction machine capable of at least two of these functions that includes the powder container.
2. Description of the Background Art
In general, electrophotographic image forming apparatuses such as copiers, printers, facsimile machines, or multifunction machines including at least two of these functions include a development device to develop latent images formed on an image carrier. In addition, cylindrical toner containers for containing toner, removably installable in main bodies of image forming apparatuses, are widely used.
For example, FIGS. 55 through 57 show a related art toner container proposed in JP-H11-109737-A. In an image forming apparatus shown in FIG. 55, a toner container 320Y is installed in a toner supply device (toner container mount) 310. The toner container 320Y includes a cylindrical bottle 320Y2 to contain a powder such as toner and a cap 320Y1 to engage an end of the bottle 320Y2. The toner supply device 310 includes a toner hopper 700, serving as a holder, to engage the other end of the cap 320Y1 of the toner container 320Y and hold the bottle 320Y2 rotatably, a bottle receiving portion 600, a coupling member 910, a spring 930, and a driving source 900. The bottle 320Y2 has spiral protrusions 320Y2a formed in an inner circumferential surface of the bottle 320Y2 and an opening positioned in one end in which the cap 320Y1 is engaged. A toner outlet is formed in the cap 320Y1.
As the bottle 320Y2 rotates, the toner contained in the bottle 320Y2 is transported along the spiral protrusions 320Y2a to the opening of the bottle 320Y2. The toner discharged from the bottle 320Y2 is discharged outside the toner container 320Y through the toner outlet in the cap 320Y1 and supplied to a development device provided inside a main body 1000 of the image forming apparatus through the toner hopper 700 in the toner supply device 310.
A coupling engaged portion 320Y2h is provided on a posterior end of the bottle 320Y2 that is an end opposite the end at which of the cap 320Y1 is located. The coupling engaged portion 320Y2h includes an outer cylindrical wall 320Y2g, a central support ring 320Y2d, and multiple spokes 320Y2b (projections) connected between the outer cylindrical wall 320Y2g and the central support ring 320Y2d. In addition, a central cylindrical recess 320Y2f and multiple divided annular recesses 320Y2e are formed in the coupling engaged portion 320Y2h. 
The coupling engaged portion 320Y2h of the bottle 320Y2 is engaged with the coupling member 910 that presses the bottle 320Y2 of the toner container 320Y by the spring 930 provided in the toner supply device 310 in the main body 1000. The driving source 900 to generate a rotary driving force is connected to the spring 930 and is provided in the main body 1000. The coupling member 910 transmits torque from the driving source 900 via the spring 930. A columnar center rotary shaft 912 and multiple tabs 911 are provided on a lateral face of the coupling member 910, facing the posterior end of the bottle 320Y2, and the multiple tabs 911 are arranged at a predetermined pitch in a rotary direction around the columnar center rotary shaft 912 on the lateral face.
With this example, the coupling member 910 is engaged with the coupling engaged portion 320Y2h by contacting the respective tabs 911 of the coupling member 910 with the spokes 320Y2b (projections) of the coupling-engaged portion 320Y2h of the bottle 320Y2. When the coupling member 910 in the main body 1000 rotates in this state, the bottle 320Y2 and the cap 320Y1 are rotated in a state in which the bottle 320Y2 and the cap 320Y1 are held by the toner hopper 700.
With this example configuration of the image forming apparatus, the toner in the bottle 320Y2 of the toner container 320Y can be discharged outside, without providing a rotary conveyance member that conveys the toner in the bottle 320Y2, thus reducing the cost of the toner container 320Y. However, in this configuration, since the toner in the bottle 320Y2 is not softened by the rotary conveyance member, the toner is more likely to form agglomeration.
In an effect to counteract the above-described problem that the toner is more likely to form agglomeration, the bottle 320Y2 is rotated in reverse in this example. More specifically, with reference to FIGS. 56 and 57, each of the multiple tabs 911 of the coupling member 910 has a setting face 911d positioned on an upstream lateral end of the rotary direction, a sloped face 911c positioned on a downstream lateral end of the rotary direction, a top face 911b, an exterior face 911a, and an inner face 911e. When the driving source 900 drives the bottle 320Y2 to rotate normally in a direction indicated by arrow E shown in FIGS. 55 through 57, the rotary driving force is exerted to the bottle 320Y2 in a state in which the setting faces 911d of multiple tabs 911 in the coupling member 910 in the main body 1000 hang with (closely contact) upstream faces of the spokes 320Y2b (projections) in the normally rotation direction of the coupling engaged portion 320Y2h of the bottle 320Y2 of the toner container 320Y. Conversely, when the driving source 900 drives the bottle 320Y2 to rotate in reverse in a direction indicated by arrow F shown in FIGS. 55 through 57, the sloped faces 911c of the multiple tabs 911 of the coupling member 910 respectively contact the spokes 320Y2b of the coupling engaged portion 320Y2h of the bottle 320Y2. Then, since the sloped faces 911c of the multiple tabs 911 cannot hang with the spokes 320Y2b of the coupling engaged portion 320Y2h of the bottle 320Y2, the sloped face 911c of the tabs 911 slide on respective edges of top faces of the spokes 320Y2b of the coupling engaged portion 320Y2h of the bottle 320Y2. At this time, the coupling member 910 that is pressed to the bottle 320Y2 of the toner container 320Y by the spring 930 is pressed back to a direction opposite the direction in which the spring force from the spring 930 is exerted, and the coupling member 910 is moved to the main body side (driving source 900 side) with to respect to the posterior end of the bottle 320Y2 in the bottle axis direction (longitudinal direction of the bottle 320Y2). Thus, the tabs 911 of the coupling member 910 cross over the spokes 320Y2b of the bottle 320Y2 of the toner container 320Y while the coupling member 910 moves to the main body side with respect to the posterior end of the bottle 320Y2. Then, the tabs 911 of the coupling member 910 are taken off from the top faces of the spokes 320Y2, and the tabs 911 enter the divided annular recesses 320Y2e positioned next to the spokes 320Y2b (projections) of the coupling engaged portion 320Y2h of the bottle 320Y2. At this time, the coupling member 910 moves to a position at which a vicinity of a base of the tabs 911 of the coupling member 910 (the lateral face of the coupling member 910) strongly contacts the top faces of the spokes 320Y2b at a burst. Thus, due to the impact of the contacting coupling member 910 and the coupling engaged portion 320Y2h, a great vibration can be generated in the bottle 320Y2, which can break the agglomeration of the toner in the bottle 320Y2.
However, since the agglomeration of the toner is broken up while the bottle 320Y2 of the toner container 320Y is rotated in reverse, the toner in the bottle 320Y2 cannot be conveyed to the toner hopper 700 at this time. Therefore, in order to alleviate the growth of the toner agglomeration, it is necessary to stop the continuous printing operation periodically and rotate the bottle 320Y2 in reverse, which increases the printing time.
Although problems arising in the bottle 320Y2 of the toner container 320Y (powder container) are described above, similar problems may occur in a powder supplying device including the powder container in an image forming apparatuses.